a = 10
b = 20
c = 30

print("and,or,not")
print(a <= b and b <= c)
print(a <= b and b >= c)

print(a <= b or b >= c)
print(a >= b or b <= c)
print(a >= b or b >= c)

print(not a >= b)

print("短路求值")
print(a >= b and 10 / 0 == 1)
print(a <= b or 10 / 0 == 1)